Molecular cytogenetic characterization of two established ESFT cell lines.

Ewing's sarcoma/primitive neuroectodermal tumor/Askin's tumor (Ewing`s sarcoma family of tumors: ESFT) is the most common type of malignant tumor of bone and soft tissue in children and young adults, and morphologically is a member of a group of small round cell tumors. We report, here, on the establishment of two human ESFT cell lines, FU-PNET-3 and FU-PNET-4, from the iliac and the chest wall, respectively, the cells of both cell lines were tumorigenic in immunodeficient mice. Histologically, both original and xenograft tumors and cultured cells were composed of small round cells with positive immunoreactivity for CD99 and Nkx2.2. Molecular biological examination demonstrated chimeric transcripts of EWSR1 exon 7 to FLI1 exon 6 in FU-PNET-3 cells, and EWSR1 exon 10 to FLI1 exon 6 in FU-PNET-4 cells. Cytogenetic analysis revealed chromosome translocation t(11;22)(q24;q12) and some secondary changes in both cultured cells. These histological, molecular biological, and cytogenetical findings indicate ESFT in both cell lines. ESFT is well studied, but its recurrent fusion genes are heterogeneous and its biological behaviors are unclear. The FU-PNET-3 and FU-PNET-4 cell lines have been well examined and may become useful tools for studying the genetic and biological behavioral properties of ESFT.